Drafting machine



Sept. 5, 1 967 BAKER ET AL 3,339,285

DRAFTING MACHINE Original Filed Oct. 25, 1961 .15 Shegzts-Shgzgt 1 INVENTOR J ATTORNEY Sept. 5, 1967 A BAKER ET AL 3,339,285

- DRAFTINQ MACHINE Original Filed Oct. 25, 1961 5 Sheets-Sheet 445 f4- 44 INVENTORS J! 13 William )Z/fraase w AlZz'sterLfia/Jer BY cl ATTORNEY Sept. 5, 1967 B K R ET AL 3,339,285

DRAFTINGMACH'INE] Original Filed Oct. 25, 1961 Sheet -S ee 5 L r I 23% Uf My;

' W I I i INVENTORS 7 7: r 35 W72" 13/! e 38 M w r z m rams q- Allmtenifiaier BY 1. immej d f M ATTORNEY United States Patent 3,339,285 DRAFTING MACHINE Allister L. Baker, Denville, and William R. Kranse,

Secaucus, N.J., assignors to Keuffel & Esser Company, Hoboken, N .J., a corporation of New Jersey Original application Oct. 25, 1961, Ser. No. 147,680, now Patent No. 3,196,544, dated July 27, 1965. Divided and this application Feb. 19, 1965, Ser. No. 442,845

8 Claims. (CI. 33-79) The present invention is a divisionof our prior application Ser.'No. 147,680, filed Oct. 25, 1961, now Patent 3,196,544, issued July 27, 1965, and relates to a drafting machine and more particularly to a drafting machine having anchor and drafting head arms pivotally connected together at one end with the other end of the anchor arm pivotally mounted on an anchor support on the edge of adrafting board and a drafting head on the other end of the drafting head arm, carrying a protractor and line guides which are maintained in parallel relation by a pulley and belt system.

Heretofore drafting machines of this type have been provided but they have been expensive to manufacture making them unavailable to schools and to students and therefore the students have not been able to take advantage of the increased efliciency in learning and Working resulting from the use of such drafting machines. One reason for the expense of manufacture was the skilled labor required to obtain the accuracy required in the parts.

An object of the present invention is to provide a drafting machine of the pivoted arm type Which is accurate in use and can be made at a cost to be available to students and to other draftsmen with limited resources.

Another object is to provide means to connect a drafting machine to a drafting table to permit removal by the owner to prevent theft thereof.

Other and further objects will be apparent as the description proceeds and upon reference to the accompanying drawings wherein:

FIG. 1 is a perspective of a fragment of a drawing board with the two arm drafting machine of the present invention mounted thereon. I

FIG. 2 is a horizontal plan view of the drafting head plate taken generally on the line 22 of FIGURE 1 below the notched disk showing in phantom outline the position retaining pawl in inoperative position for cooperation with the notched disk also shown in phantom outline and showing the clamp for setting intermediate angular adjustments and also showing the leaf spring detent operative on the control lever for the pawl operated H slide forretaining the pawl in operative or inoperative positions.

FIG. 3 is a vertical section taken substantially on line 33 of FIG. 1 showing the drafting head plate adjustably mounted in the bore of the control pulley hub and showing the usual pawl releasing arrangement and the novel push button means to restore the pawl to operative position.

FIG. 3A is a fragmentary section on line 3a-3a of FIG. 3 showing the pawl control bar in the cup and the pawl operating wheel.

FIGURE 4 is a section taken substantially on line '44 of FIG. 2through the infinite position clamping control to retain the drafting head in adjusted positions.

FIG; 5 is a plan view of the pivotal connection joint between the arms which are assumed to be in superimposed position and showing the adjustment for tensioning the straps.

FIG. '6 is a vertical axial section of the two arms of the draftingmachine taken substantially on line 6-6 3,339,285 Patented Sept. 5, 1967 of FIG. 5 showing the means for obtaining the frictional adjustment between the arms and illustrating the bearing structure.

FIG. 7 is a plan view of the anchor end of the anchor arm showing a portion of the anchor bracket mounted on a drawing board.

FIG. 8 is an axial section taken substantially on line 88 of FIG. 7 through the pivot connecting the anchor arm and the anchor bracket.

FIG. 9 is a horizontal section just above the anchor pulley taken on line 99 of FIG. 8 with the arm mounting fitting removed therefrom.

FIG. 10 is a horizontal section taken substantially on line 10-10 of FIG. 8 showing the shape of the T-groove which serves to retain the anchor pulley in fixed adjusted position.

FIG. 11 is an enlarged fragmentary circumferential section looking toward the axis taken along the pulley grooves of FIGS. 10 and 12 through the locking screw and nut of the anchor pulley retaining structure.

FIG. 12 is. a fragmentary enlarged section taken substantially on line 12-12 of FIG. 11 showing the bolt head of the locking bolt in the T-groove.

Referring more particularly to the drawings, a drafting board 15 has mounted thereon an anchor clamping bracket 16 which is held in position by a clamping screw 17 and by. any one or more screws passing through counter-sunk screw receiving apertures in a flange 18 which anchor bracket flange is covered by a resilient rubber-like cover 19 secured thereto by adhesive or other means to prevent damage to line guides. The anchor bracket includes an upstanding bearing boss 20 which is perpendicular to the clamping surface of. the flange 18 and an angularly adjustable anchor pulley 21 having an integral tubular shaft 22 which is rotatably adjustable in the anchor bearing boss 20. The anchor pulley 21 is provided with a circumferential dovetail type groove 23 of T-shape in radial cross-section with such groove having the flange portions at 24 to provide for the reception of a square head 25 of an angular position locking bolt or screw 26, the shank of which bolt passes through an aperture in a lug 27 extending radially from theupper end of the anchor bearing boss 20 as clearly shown in FIGS. 10, 11, and 12. The anchor pulley 21 is provided with a circumferential V-groove 28 on its upper surface while an Allen head stop screw lug member 29 is threadedly received in a threaded aperture extending between grooves 23 and 28 and such stop screw 29 projects into the path of a stopv lug 30 extending into aciroular recess of a first fitting 31 which recess 32 receives the anchor pulley 21, said fitting having a pair of parallel tube receiving sockets 33 extending tangentially in one direction. A pivot shaft 34 is fixed to said first fitting 31 by means of one end of such pivot shaft 34 extending into a counter. bore in the recess of fitting 31 and being held in position by a screw 35 passing pivot shaft 34. The pivot shaft 34 is retained in the tubu lar shaft 22 of the anchor pulley 21 by a split ring 36 which also serves to retain needle bearings 37 and any suitable spacing elements in the circumferential space between the pivot shaft 34 and the anchor pulley tubular shaft 22 to assure ease of movement of the fitting 31 and of the anchor and drafting head arms of the drafting machine. The pulley 21 is retained in position by the locking bolt 26 and a peripherally grooved hexagonal nut 38 held in operative position in a broached hexagonal opening in wrench handle 38' having an Allen-head screw 39 threaded through the periphery of the wrench 38' and into the groove of the hexagonal nut 38 so that the hexagonal nut may bear directly against a washer contacting the lug 27, thereby positively retaining the drafting machine on the anchor clamp and also maintaining the desired angular adjustment of the anchor pulley 21.

A second fitting 40 provided with a circular recess and a pair of sockets in alignment with the sockets of the first fitting is connected by tubes 41 to the first fitting 31, said tubes being freely rotatably in their sockets and the structure being maintained in connected condition by the tension of the control stra 42 which engages the periphery of the anchor pulley 21 and the periphery of the upper portion of a double pulley 43. The tension of the control strap is adjusted by turnbuckle type device 42A.

A third fitting 44 similar to the second fitting 40 and having a circular recess and a pair of tangentially extending sockets is positioned with its recess facing the recess of the second fitting 40, said second and third fittings having bearing bosses 40A and 44A with counter bores 40B and 44B respectively. Said second and third fittings are pivotally mounted on a tubular shaft 45 extending through the bosses and through a bore in the web of the double pulley 43 which provides for rotation of such double pulley 43, the fittings 40 and 44 being rotatable on the tubular shaft 45 by means of needle bearings 46 which are maintained in spaced relation and in operative position by washers 47 abutting the boss of double pulley 43 and by split rings 48 in grooves of shaft 45 which maintain the parts in assembled condition. Friction washers 49 of cork are positioned against wear washers 50 in each recess 40B and 44B.

A reaction washer 51 of smooth exterior curvature corresponding to the curvature of the fitting 40 is provided with a counterbore to freely receive the locking ring 48. A headed friction-producing bolt 52 passes through washer 51 and into the tubular shaft 45 and extending to adjacent the other end of such tubular shaft. A flanged tubular nut 53 having a circumferential groove receiving split ring 48 has an internally threaded tubular portion thereof extending into a counterbore in the other end of tubular shaft 45 and is threaded onto the end threads of friction-producing bolt 52. To retain the nut 53 against rotation in the tubular shaft 45 the tubular shaft is provided with diametrically opposite pin receiving slots 54 and the nut is provided with a transverse bore which receives a pin 55 for preventing relative rotation of said nut with respect to said tubular shaft 45 whereby frictional force between the flanged head of nut 53 and washer 51 can be obtained, it being apparent that a suitable slot or spaced wrench-receiving apertures may be provided in nut 53 to prevent rotation of the nut assembly during adjustment. The bolt 52 is provided with a nylon insert 52A in a transverse bore and such nylon insert is sufficiently long to engage the threads of the nut 53 to retain the nut and bolt in adjusted condition.

In normal use the pulley 43 is fitted with sufficient tightness on tubular shaft 45 to prevent relative rotation therebetween and merely by holding the parts of the draft ing machine in fixed relation the tubular shaft and the nut 53 will be prevented from rotation and frictional adjustment can be obtained by the use of a screwdriver in the slot of a friction-producing bolt 52.

A fourth fitting 56 having a downwardly opening circular recess and a pair of parallel tangentially extending sockets is connected by tubes 57 to the third fitting 44. The fourth fitting has a central boss with a bearing bushing 58 therein which receives a hollow shaft 59 of a third pulley 60 providing a drafting head support, which pulley is retained in position by a split ring 61 abutting the upper surface of bushing 58 with the web of pulley 60 lying beneath the bushing, said pulley being provided with a circumferential rabbet which receives an annular protractor 62, a spacing ring 63 and a notched disc 64 which are held in fixed position to the third pulley 60 by a plurality of screws 65. The web of the pulley 60 is spaced above the lower side of the pulley providing a recess for flange 66A of tubular flanged shaft 66, the

flanged shaft being rotatable in the bore of the third pulley shaft 59. The flanged tubular shaft is provided with a shoulder providing clearance above the tubular pulley shaft by reducing the diameter of the shaft 66A and such reduced portion is received in a bore in the bottom of cup 67 which cup is secured to the shaft by a nut 68. The cup 67 has a radial flange 69 on the outer circumference of the cup 67 and rotatably supported on the cup 67 and engaging the flange 69 is a pawl-operating wheel 70 having a boss 71 extending extending along the periphery of the cup. The cup 67 of the pawl-operating wheel is provided with circumferential slots bounded by edges 72, 72. The boss 71 has circumferential slots defined by edges 72A and 72B spaced apart somewhat greater than edges 72. A drafting head rotating knob handle 73 is fixed to the cup 67 by a screw 74 and such knob is provided with a central bore and a counterbore which receives a flanged push button 75 having a boss 76 slidably mounted in the bore of the knob 73 and normally urged to the inoperative position shown in FIG. 3 by a coiled compression spring 77, the knob being held in assembled relation by a split ring 78. A double tapered lever 79 having a fulcrum flange intermediate its ends is positioned in the passage of the flanged hollow shaft 66, one end of said double tapered lever having a bore therein and the other end having an enlargement. A pin 80 having a head at one end and an intermediate enlargement is mounted in the bore of said one end of said double tapered lever 79. A control bar 81 having a central aperture is positioned in the cup 67 and extends into the slots in boss 71 and cup 67 with the ends of such control bar in the path of the abutment surfaces 72 Of the cup and abutment surfaces 72B of host; 71 of the control wheel 70 whereby rotation of the control wheel 70 causes displacement of one end of the control bar 72 while the other end of the control bar remains in en gagement with the abutment edge 72 as a fulcrum there by moving the aperture in control bar 81 from the osi tion shown in FIG. 3 to a displaced position as shown in phantom by dash-dot line in FIG. 3A and moving double tapered lever 79 from the position shown to a position in which the angle extends from the upper left to the lower right as viewed in FIG. 3. This dotted line position of FIG. 3A corresponds to the phantom dash-dot line of the pawl in FIG. 2. The boss 76 of the push button 75 is provided with a conical downwardly flaring bore 76A which in the inoperative position shown permits the double tapered lever 79 to oscillate from the full line pawl engaging position shown to a pawl releasing position.

Mounted on the flange 66A of the flanged hollow shaft 66 is the drafting head plate 83 which is fixed to such flange 66A by suitable screws and such plate 83 is provided with a slot 84 in which a slide 85 is mounted, such slide being urged to a retracted position by a tension spring 85A and being under the control of double tapered lever 79 of which the enlarged lower end is received in an aperture 85B in the slide. The aperture 85B is provided with an inwardly extending flange at its lower end thereby retaining double tapered lever 79 in operative position between control bar 81 and slide 85. The slide 85 is retained in the slot 84 by a control lever 86 pivotally mounted on one side of the slot 84 on the drafting head plate and extending underneath the drafting head plate and under slide 85 and operatively connected to the slide 85 by a rivet 85C fixed to the slide and extending downwardly into a radial slot in the control lever 86. Additional means such as a strut between the walls of the slot 84 may assist in retaining the slide. The otherend of the slide 85 is operatively connected by a rivet 85D fixed to and extending upwardly from the slide 85 and received in a slot of a pawl 87 which pawl is pivotally mounted on the upper surface of drafting head plate 83. The projection tip of such'pawl 87 is receivable in any one of the notches of the notched disk 64 thereby retaming the drafting head plate in fixed position with retrol lever 86 projects beyond the other side of slot 84 and has a tooth 86A which engages a wedge-shaped cam portion of a leaf spring 863, which leaf spring is adjustably secured to the under surface of the plate 83 by suitable screws 86C passing through slots in a flange fixed to the leaf spring 86B whereby the control lever 86 will be retained in either of the positions shown in FIG. 2 in which the projection of the pawl 87 is in engagement with a notch in the notched disk 64 as shown in full lines holding the drafting head in one of the 15 adjusted positions or the pawl is in the other position as shown in dash-dot lines in which the pawl is released. In the released position the left edge of the tooth 86A of control lever engages the right edge 86D of the wedge-shaped cam portion of the leaf spring 86B thereby retaining the slide 85 against the tension of the spring 85A corresponding to the dash-dot line position of the parts in FIG. 3A whereby the drafting head plate 83 is free to move to any azimuth position relative to the protractor 62.

To retain the drafting head plate in fixed position relative to the protractor when the pawl is out of engagement with the notched disk, a flanged Z-shaped clamp element 88 (FIGS. 2 and 4) is positioned on the drafting head plate 83' with one end of the base of the Z-shaped clamp element against the plate 83 and a flanged screw 89 passes through an aperture in the drafting head plate '83 and projects thereabove, passing through an enlarged aperture in the stem of the Z-shaped clamp element 88 and threaded into the threaded bore of a lever 89A whereby motion of the lever will cause movement of the Z-shaped clamp 88. Precise adjustment is obtained by a locking screw 89B threaded into the drafting head plate with its head engaging the flange of flanged screw 89 to hold the flanged screw 89 in a position so that limited movement of lever 89A will produce the desired clamping action. Mounted on the drafting head plate 83 is an abutment 88A underlying the protractor 62 beneath the flange 88B of the flanged Z-shaped clamp 88 whereby the clamping action produced will react on the abutment 88A and avoid objectionable distortion. It will be apparent that the movement of the pushbutton 75 downwardly when the pawl is in the full line position of FIGURE 2 causes the lever 79 to move to a central position thereby moving the pawl 87 to an intermediate position in which the pawl is disengaged from the notches of the notched disk 64 and the drafting head plate 83 can then be turned to any desired angle to position the scale carying lugs 90 and 91 in the desired position, and upon release of the push-button 75 the pawl will engage the adjacent notch of the notched disk 64.

When it is desired to restore pawl 87 to operative position depression of button 76 causes double tapered lever 79 to be restored to the full line position so pawl 87 engages one of the notches in notched disk 64.

It will be apparent that the various pulleys are connected by straps 42 tensioned sufiiciently by turnbuckle type tension elements 42A to maintain the fittings in secure assembled relation and also to assure that there is no slipping between the straps 42 and the pulleys cooperating therewith.

From the above description it will be apparent that the present invention provides means to maintain the line guide scale carrying lugs 90 and 91 of drafting head plate 83 in proper relation so that line guide scales 90A and 91A carried thereby will be maintained in their parallel relation or in a definite angular relation in accordance with the adjustment obtained between the protractor 62 and an index 93 fixed to the drafting head plate 83 which index also serves as a housing for the pawl 87.

It will be apparent that various changes may be made within the spirit and scope of the invention as defined in the valid scope of the appended claims.

What is claimed is:

1. An anchor structure for a drafting maching compris- 6 ing a bracket having a bore therein, means to support said bracket on a drafting surface-with said bore substantially perpendicular thereto, an anchor pulley rotatably mounted in said bore, a fitting rotatably mounted on the axis of said pulley and on the axis of said bore and having communicating sockets extending substantially tangential to said pulley, said pulley having a circumferential T-shaped groove on one side thereof and having a circumferential groove on the other side thereof, a stop lug so said fitting projecting into said circumferential groove, a stop lug member on said anchor pulley projecting into said circumferential groove for cooperation with said stop lug on said fitting to limit the relative rotation between said anchor pulley and said fitting, a lug on said bracket underlying said T-shaped groove and having an aperture therethrough in registry with said T-shaped groove, a non-circular headed locking bolt positioned in the aperture in said lug and having its head extending into said T-shape-d slot, an adjustable nut means cooperating with said locking bolt and with said lug for retaining said anchor pulley wheel in fixed angular relation.

2. An anchor structure for removable mounting of a drafting board comprising a bracket, means to secure the bracket to the edge of a board, a hollow boss mounted on said bracket and extending in a substantially perpendicular direction with respect to the board providing a stub shaft receiving bearing surface, a pulley having an integral tubular stub shaft received in the bearing surface of the boss of said bracket, said boss and said pulley having cooperating thrust bearing surfaces whereby when the stub shaft of the pulley is within the bearing of the boss said cooperating thrust bearing surfaces are'in snug engagement, said pulley having a dovetail groove on the surface adjacent said boss outwardly of said thrust bearing surfaces, a lug extending outwardly of said boss and underlying said circumferential dovetail groove in said pulley and having a bolt receiving aperture in registry with said dovetail groove, a bolt having a non-circular head mounted with its head in said dovetail groove and extending through said bolt-receiving aperture in said lug, a nut on said bolt, a handle mounted on said nut and movable a suflicient angular distance to provide clamping action between the head of the bolt and the walls of the dovetail groove to fix the pulley relative to the boss means to adjust the handle on the nut to provide the correct range of operation of the clamping action of said non-circular head against the dovetail groove, said dovetail groove having an enlarged portion providing for removable reception of the head of the bolt, a fitting having a stub shaft rotatably received in the bore of the tubular stub shaft of the pulley, means to prevent axial separation of the fitting and the pulley means, to limit the extent of rotation of the fitting relative to said pulley, and means on said fitting for supporting an arm of a drafting machine, said structure providing for axial removal of the drafting machine from the anchor support by releasing said non-circular headed bolt and aligning the non-circular head of the bolt with the enlargement of said groove and applying an axial force removing the pulley having a hollow shaft and the fitting including the drafting machine from the bracket.

3. The invention according to claim 2 in which a groove is provided in the upper surface of the pulley, a cooperating abutment is mounted on the fitting and extending into the groove, and a removable abutment is mounted on said pulley for cooperating with the abutment on the fitting whereby the rotation of the fitting with respect to the pulley is limited.

4. A drafting machine comprising an anchor boss, means for mounting said anchor boss adjacent an edge of a drafting board, said anchor boss having a bore therethrough adapted to extend perpendicularly to the drafting board, an anchor belt wheel having a stub shaft received in said bore of said anchor boss, said anchor belt wheel having a dovetail type circumferential groove, said groove including an enlarged opening for receiving a non-circular head of a zero-position locking bolt, an anchor end fitting rotatably mounted on said anchor belt wheel and having a stop lug projecting toward said anchor wheel, a cooperating stop lug member on said anchor wheel projecting toward said anchor end fitting for engagement with the stop lug on said anchor end fitting to limit the relative rotation between said anchor belt wheel and said anchor end fitting, a lug extending from said boss, a locking bolt having a non-circular head positioned in said dovetail type groove with the shank passing through said lug extending from said boss and a nut receiving the shank of the non-circular headed locking bolt for securing said anchor belt wheel in fixed position on said anchor boss.

5. A drafting machine comprising an anchor boss, means for mounting said anchor boss adjacent an edge of a drafting board, said anchor boss having a bore adapted to extend perpendicularly to the drafting board, an anchor belt wheel having a stub shaft received in said bore of said anchor boss, an anchor end fitting rotatably mounted in said anchor belt wheel and having a stop lug projecting toward said anchor belt wheel, a cooperating stop lug member on said anchor belt wheel projecting toward said anchor end fitting for engagement with the stop lug on said anchor end fitting to limit the relative rotation between said anchor belt wheel and said anchor end fitting, and locking means to removably fix said anchor belt wheel in the bore of said boss in a selected fixed position for proper base line registration of the drafting machine whereby the anchor belt wheel with the anchor end fitting including the drafting machine supported thereby may be applied to and removed from the anchor boss and a different drafting machine applied.

6. The invention according to claim 5 in which the anchor belt wheel stub shaft is tubular, the anchor end fitting has a shaft rotatably mounted in the tubular stub shaft of the anchor belt wheel, and the locking means includes a threaded bolt reacting between said boss and said anchor belt wheel.

7. A drafting machine comprising an anchor boss, means for mounting said anchor boss adjacent an edge of a drafting board, said anchor boss having a bore adapted to extend perpendicularly to the drafting board, an anchor belt wheel having a tubular stub shaft removably received in said bore of said anchor boss, an anchor end fitting having a shaft rotatably mounted in the tubular stub shaft on said anchor belt wheel whereby the anchor belt wheel with the anchor end fitting and the drafting machine attached thereto may be applied to and removed from the anchor boss, and means to fix the anchor belt wheel in position relative to the boss so the drafting machine will register with the desired base line of a drawing on the drafting board and a different drafting machine may be applied to the boss so the said different drafting machine will register with the base line of the same or different drawing on the drafting board.

8. The invention according to claim 7 in which the means to fix the anchor belt wheel in position relative to the boss includes a screw.

References Cited UNITED STATES PATENTS 1,208,340 12/1916 Little 33-792 2,438,220 3/1948 Ketting 33--79.3

LEONARD FORMAN, Primary Examiner.

H. N. HAROIAN, Examiner. 

1. AN ANCHOR STRUCTURE FOR DRAFTING MACHING COMPRISING A BRACKET HAVING A BORE THEREIN, MEANS TO SUPPORT SAID BRACKET ON A DRAFTING SURFACE WITH SAID BORE SUBSTANTIALLY PERPENDICULAR THERETO, AN ANCHOR PULLEY ROTATABLY MOUNTED IN SAID BORE, A FITTING ROTATABLY MOUNTED ON THE AXIS OF SAID PULLEY AND ON THE AXIS OF SAID BORE AND HAVING COMMUNICATING SOCKETS EXTENDING SUBSTANTIALLY TANGENTIAL TO SAID PULLEY, SAID PULLEY HAVING A CIRCUMFERENTIAL T-SHAPED GROOVE ON ONE SIDE THEREOF AND HAVING A CIRCUMFERENTIAL GROOVE ON THE OTHER SIDE THEREOF, A STOP LUG SO SAID FITTING PROJECTING INTO SAID CIRCUMFERENTIAL GROOVE, A STOP LUG MEMBER ON SAID ANCHOR PULLEY PROJECTING INTO SAID CIRCUMFERENTIAL GROOVE FOR COOPERA- 